AN1857 Freescale Semiconductor / Motorola, AN1857 Datasheet - Page 15

• Manufacturer Part Number: AN1857
• Description: A 3-Phase ac Induction Motor Control System Based on the MC68HC908MR32
• Manufacturer: Freescale Semiconductor / Motorola

Optoisolation
Board
AN1857
MOTOROLA
The function of the optoisolation board is to provide a galvanic isolation
barrier between the control board’s I/O, both analog and digital, and the
high-voltage system power board’s I/O. These isolated signals, to and
from the optoisolation board, are connected by two 40-pin ribbon cables.
Pin assignments for both connectors are the same. Signal flow through
the optoisolation board, in both directions, is a one-to-one relation of its
source. For a more detailed description of the optoisolation board, refer
to Motorola’s Embedded Motion Control Series Optoisolation Board
User’s Manual, Motorola document order number MEMCOBUM/D.
Figure 8
Zero_cross_B
Zero_cross_C
Zero_cross_A
MUX_A
MUX_C
MUX_B
Freescale Semiconductor, Inc.
For More Information On This Product,
shows a block diagram of the optoisolation board.
Go to: www.freescale.com
Figure 7. Zero Cross and Back-EMF Circuit
1/4 MC74HC03AD
1/4 MC74HC03AD
1/4 MC74HC03AD
+5V_D
5.6 k
1/4 MC74HC03AD
+5V_D
System Hardware
Application Note
5.6 k
BEMF_z_c
15